Such a volumetric flow controller for adjusting a volumetric flow through a flow channel in an air conditioning and ventilation system is known for example from EP 1 950 508 A2.
Such volumetric flow controllers are an important element of modern ventilation technology. They enable entire buildings or even only single rooms to be supplied with defined amounts of air by measuring, analyzing and regulating the air flows of the room air supply. A pressure difference in the flow channel is determined by means of a differential pressure sensor and an actual value is determined therefrom. Said value is compared with a stored target value in a controller. In the case of a deviation, the controller adjusts a control flap provided in the flow channel in order to set the volumetric flow accordingly between a minimum and a maximum permissible volumetric flow. In this case, the differential pressure sensor can be designed as a dynamic flow sensor or as a static pressure sensor. In both cases, height-independent VAV control should be possible. This is achieved with the simultaneous use of a further pressure sensor for determining the barometric air pressure of the surroundings. The differential pressure sensor provides a corrected signal proportional to the air speed in the flow channel.
The volumetric flow controller known from EP 1 950 508 A2 comprises a rotary switch as a first operating element for selecting one of a plurality of control and/or configuration parameters and a rotary knob as a second operating element for adjusting the value of the respective selected parameter. The currently set value of the parameter selected with the rotary switch is displayed on a display. A target parameter is selected by adjusting the rotary switch (parameter switch), for example using an externally applied scale, the value of said parameter being adjusted with the rotary knob (setting potentiometer or editing switch).
In the case of the volumetric flow controller known from DE 20 2004 010 819 U1, two potentiometers are provided for setting the minimum and maximum permissible volumetric flows. Using an externally applied scale, the minimum and maximum volumetric flows can be set without problems by means of a potentiometer in each case. The input of further control parameters (for example “maximum measurement range”, normal or inverse direction of rotation of the control flap, etc.) and the display of the control drive data are carried out with a separate control part that is connected to the volumetric flow controller.
In the case of the volumetric flow controller known from U.S. Pat. No. 5,161,100, a switch is provided for setting each of the control parameters of a PI controller (proportional component, integration time). Further functions are the selection of configuration parameters that can be varied by the aforementioned switch.
By contrast, it is the object of the present invention to further simplify the operation of a volumetric flow and pressure controller of the aforementioned type.